Purpose. This research was to see how effective and feasible school-based comprehensive strength training programs are in improving muscular fitness and perceived physical competence in Chinese male adolescents. Methods. A total of 123 participants (
13.46
±
0.60
years) were randomized to comprehensive strength training intervention group (CST) (
n
=
62
) and the control group (CON) (
n
=
61
). The training sessions were performed three times a week for ten weeks in CST. Muscular fitness (i.e., muscular strength, power, and muscular endurance) and perceived physical competence were assessed at initial testing and final testing. Results.The subjects in the CST significantly improved their mean performance in standing long jump (
p
<
0.05
), vertical jump (
p
<
0.05
), 1 min push-ups (
p
<
0.05
), 1 min sit-ups (
p
<
0.05
), handgrip strength (
p
<
0.05
), and perceived physical competence (
p
<
0.05
) after the intervention. Moreover, the CST were greater in standing long jump (
p
<
0.05
), vertical jump (
p
<
0.05
), 1 min sit-ups (
p
<
0.05
), handgrip strength (
p
<
0.05
), and perceived physical competence (
p
<
0.05
) compared to the CON, but no in 1 min push-ups (
p
>
0.05
). Conclusions. The comprehensive strength training interventions designed in this study can significantly increase male adolescents’ muscular fitness, especially in the lower extremity muscle power and abdominal core endurance, and can enhance their perceived physical competence.